Composite punching and dimpling tool



O. G. RIESKE COMPOSITE `PUNCHING AND DIMPLING TooL Dec. 16; 1947.

` Filed July 3, 1944 chine, wherein lll indicates the Patented Dec. 16, 1947 COMPOSITE PUNgHING AND DIMPLING Otto G. Rieske, Bualo, N. Y.

Application July Claims.

This invention relates generally to certain new and useful improvements in punch apparatus but more particularly to a device or apparatus for both punching and dimpling sheet metal and the like for riveting purposes.

It has for one of its objects to provide an apparatus of this character which is so designed and constructed as to effectually accomplish in a single operative stroke the clamping of the work as well as the dimpling and punching thereof.

Another object of the invention is to provide a novel arrangement of clamping, dimpling and punching dies which is simple, compact and inexpensive in construction, efficient and reliable in operation, and which is not liable to get out of order.

A further object is to provide a unitary clamping7 dimpling and punching die assembly which employs hydraulic pressure for controlling the sequential operations of clamping, dimpling and punching.

Other features of the invention reside in the construction and arrangement of parts hereinlafter described and particularly pointed out in the appended claims.

In the accompanying drawings:

Figure l is a fragmentary side view of a punch press showing my improved tool installed thereon. Figure 2 is an enlarged vertical section taken on line 2.-2, Figure 1. Figure 3 is a horizontal section on line 3-3, Figure 2. Figures 4, 5 and 6 are fragmentary vertical sections showing the sequence operation oi the tool elements for clamping the work in place, for dimpling, and ior punching, respectively.

Similar characters o reference indicate corresponding parts throughout the several views.

.By way of example, my composite tool has been shown as installed on a punch press or like mamachine-yoke, H the pedestal for supporting it, and l2 the power unit to which the actuating plunger I3 for transmitting the operative strokes to the tool is connected. Mounted on the lower portion of the yoke is the anvil or die i5 on which the work l5 to he punched and dimpled is supported.

The improved tool, which has been designed to efciently perform in one sequential operation the clamping of the work to the anvil, the dimpling of the work to provide a counter-seat lli for a rivet or the like, and the punching of a hole I'l in the work axially of such seat, consists of a retaining body or cylinder i8 open at its lower end and having a counter-bored portion in its upper end forming a pocket or chamber lil for receiving 3, 1944, Serial No. 543,391

oil or a like fluid medium which is adapted to be subjected to pressure by the actuating plunger I3 for transmitting operative strokes to the various tool elements. Screwed or otherwise tted in the upper end of this cylinder is a guide 20 for the plunger, the lower ends of the guide and the plunger forming the top wall of the chamber I9. it will be noted in Figure 2 that the level ofthe oil in this chamber is such that it extends partly into the bore of the plunger-guide and in the elevated position of the plunger" there is a small air or vacuum space.

Fitted in the cylinder I8 for actuation by the hydraulic ram effect produced by the plunger and oil are the tool elements 2|, 22 and 23 which are disposed in concentric or telescoped relation for relative movement in response to the strokes of the plunger. The outermost element 2l, which is the work-engagingA or clamping element, is in the form of a sleeve indirect bearing engagement with the cylinder, being exposed at its upper end to the oil in the chamber I9 while its lower end normallyextends slightly below the corresponding end of the cylinder and terminates in an inwardly-facing annular flange 24 constituting a stop shoulder for limiting the downward or operative displacement of the next adjoining or dimpling element 22. The latter is likewise sleeve-like in form. being guided on the clamping element, and terminates at its lower end in a dimpling stud or projection 25 whichvnormally extends slightly below the work-engaging face of the clamping element 2 l. This dimpling element also is provided adjacent its lower end with an inwardly-facing annular ange 26 constituting a stop shoulder for limiting the downward or operative displacement of the innermost tool element 23. This latter element is the punching die and is in the form of a rod terminating at its lower end in a downwardly-facing shoulder 21 adapted to abut the shoulder 26 for limiting its downward displacement relative to the dimpling element. Normaly the lower end of this punching element extends somewhat below that of the dimpling element while the upper ends of the several tool elements 2|. 22 and 23 are substantially hush and severally form the oor of bottom of the oil chamber I9. One or more shims 28 are disposed between the shouldered ends oi the tool elements 2l and 22 to obtain the required accuracy of operation of such elements. The crosssectional areas of these tool elements are such that the outer or clamping element 2l has the largest area, the intermediate or dimpling element 122 the next largest area, and the innermost or punching element 23 the least area, so that when the hydraulic pressure exerted by the plunger is transmitted to these elements they will respond in the sequence named.

In oper-ation, assuming a sheet of material to be placed on the anvil I4, the power unit I2 is operated to lower the plunger I3 and accordingly the tool element 2| is lowered to clamp the sheet firmly to the anvil, after which the dimpling and punching elements 22 and 23, respectively, are lowered to produce the dimple or counter-seat I6 and the rivet hole I'I in the sheet. On the return stroke of the plunger, the tool elements are automatically retracted to their normal position by the resulting vacuum which :also serves to retain the tools in such position in readiness for the next operative stroke.

I claim as my invention:

1. A tool of the character described, comprising a punch and die for forming an opening in a sheet of material, a dimpler disposed in correlation with said punch and die for movement relative thereto for forming a dimple in the material about the punch-formed opening, a pressure member disposed in correlation with said .dimpler for clamping the material between it and the die during the punching and dimpling operation, said punch, dimpler and pressure plate being disposed in telescopic relation for independent relative movement, and duid-pressure means including a cylinder housing said parts and a plunger in operative endwise relation to and for actuating said parts, through lthe medium of the fluid, in sequence as determined by Athe relative areas thereof exposed to such uid pressure.

2. A tool for punching and dimpling, comprising a punch, a dimpler and a pressure plate, said parts being disposed in axial relation for relative movement, a retaining cylinder for housing such parts and including an oil chamber in the upper end thereof, the upper ends of such parts being exposed to and forming the licor of said oil-chamber, and a plunger operable in said chamber for exerting a pressure on the oil therein for transmitting operative strokes to said punch, dimpler and pressure plate in sequence.

3. A tool of the character described, comprising a cylinder open at its lower end and having a piston guide at its upper end, said cylinder and guide being disposed to provide an oil chamber in the upper end of the cylinder, a piston operable in the guide and said chamber, and punch, dimpling, and work-clamping elements disposed in `concentric relation axially of -said cylinder for relative movement toward and from the work inder and providing an oil chamber between such parts and the upper ends of the punch, dimpling and clamping elements, and a piston operable in said guide and said chamber for transmitting operative strokes to said elements by hydraulic pressure to successively bring the clamping element, the dimpling element and the punch elepunching OTTO G. RIESKE.

REFERENCES CITED The following references are of record ln the le of this patent:

UNITED STATES PATENTS Number Name Date 2,356,526 Mayer et al. Aug. 22, 1944 928,256 Grissom July 20, 1909 2,168,377 Wales Aug. 8, 1939 2,308,953 Brown Jan, 19, 1943 2,348,875 Beard May 16, 1944 

